1. Field of the Invention
The field of the invention relates to circuitry processing signals from a higher voltage domain using devices configured to operate in a lower voltage domain.
2. Description of the Prior Art
Advances in the field of electronics have led to a reduction in both core and input-output power supplies in order to increase processing speeds and reduce power consumption. The transistor dimensions and oxide thickness have also decreased for the same speed reasons.
Thus, for devices of 45 nm, the “standard” external power is now 1.8V where it was previously 3.3V or 2.5V. In order to be able to reach high frequencies the oxide thickness has been decreased and is now around 28 to 32 Å for 1.8V devices (where previously it was about 50 Å).
There are therefore now some apparatus that operate with the new devices in circuits that receive or generate signals in the old higher voltage domains. For example, to be compatible with some older chips and a few standard protocols some input-output cells must receive signals from the older chips at the nominal 3.3V and output signals at the nominal 1.8V for circuitry operating at these levels, while using the new devices that operate at the nominal 1.8V.
In order to ensure that these devices are not overstressed with the accompanying problems of oxide breakdown and lifetime degradation due to HCl (hot carrier injection) precautions need to be taken.
Embodiments of the present invention seek to provide a receiver capable of receiving signals from a higher voltage domain and outputting these signals in the new lower voltage domain, using modern devices designed for the new lower voltage domain.